src/int24.cpp:37:10: error: invalid operand for instruction
        "\tmovzbl  %%dl, %0\n"
         ^
<inline asm>:14:15: note: instantiated into assembly here
        movzbl  %dl, %r8b
                     ^~~~
src/int24.cpp:38:10: error: invalid operand for instruction
        "\torq     %%rcx, %0\n"
         ^
<inline asm>:15:16: note: instantiated into assembly here
        orq     %rcx, %r8b
                      ^~~~
2 errors generated.

asm("\taddl    %2, %1\n"
    "\tseto    %0\n"
    "\tmovl    %1, %%ecx\n"
    "\tshll    $8, %%ecx\n"
    "\tsarl    $31, %%ecx\n"
    "\tmovl    %1, %%edx\n"
    "\tshrl    $23, %%edx\n"
    "\tandl    $1, %%edx\n"
    "\tandl    $8388607, %1\n"
    "\tandl    $-8388608, %%ecx\n"
    "\torl     %1, %%ecx\n"
    "\torb     %0, %%dl\n"
    "\tshlq    $32, %%rcx\n"
    "\tmovzbl  %%dl, %0\n"
    "\torq     %%rcx, %0\n"
    : "=r"(overflow), "+r"(lhs)
    : "r"(rhs)
    : "cc", "rcx", "edx");

f1(int):                                 # @f1(int)
        mov     eax, edi
        shl     eax, 8
        sar     eax, 31
        and     eax, -8388608
        ret
f2(int):                                 # @f2(int)
        mov     eax, edi
        and     eax, 8388608
        neg     eax
        ret

func add(lhs: Int32, rhs: Int32) -> (Bool, Int32) {
    let x = lhs.addingReportingOverflow(rhs)
    let v = (x.partialValue << 8) >> 8;
    return (x.overflow || x.partialValue != v, v)
}

pair<bool, int24_t> int24_t::add_with_overflow(int24_t other) const noexcept {
    int32_t edi = this->value + other.value;
    return { static_cast<bool>(edi & 0x800000), int24_t{ (edi & 0x7fffff) | -(edi & 0x800000) } };
}

yx^y<0
xy>0